alpha, beta-bis(hydroxyphenyl) alkanones and methods for their production



United States PatentO s a,fi-BIS(HYDROXYPHENYL) ALKANONES AND METHODS FOR THEIR PRODUCTION Kurt J. Rorig, Chicago, Ill., assignor, by mesne assignments, to G. D. Searle & Co., Skokie, Ill., a corporation of Delaware No Drawing. Application November 14, 1952,

Serial No. 320,616 10 Claims. (Cl. 260-590) The present invention relates to novel organic compounds and particularly. to a,B-bis(hydroxyphenyl)- alkanones and to methods for their production. The compounds which constitute my invention can be represented by the following general structural formula alkanoamide ofthe type i OONH: lloweralkyl) (HO),- R OH wherein R is defined as'hereinabove, described in my application Serial No. 167,265, filed June 9, 1950, now abandoned and my application, Serial No. 228,999, filed May 29, 1951, which was issued on January 19, 1954 as. U. S. Patent 2,666,789, can be hydrolyzed with strong alkali to form the acid of the type (lower a1 1) C O O H ky (H it 7 OH The free hydroxyl groups can then be protected by esterification or etherification, and the acid group converted to an acyl chloride group of the type (lower alkyl) C 0 Cl De 3 (XO).. R OX wherein X is an alkyl or acyl group which is removable by hydrolysis. This acid chloride is then treated with an organometallic compound, such as a dialkylcadmium, to produce a The protective X groups can be removed by the usual methods of hydrolysis such as with alkali or by addition compounds which 'comprisethis invention and methods for producing same. However, this invention is not to be 2,768,210 Patented Oct. 23, 1956 of aluminum bromide and decomposition of the resulting complex with mineral acid. 7

'Another useful method is illustrated by the following procedure. An acrylonitrile of the type (R0). OR

wherein R is alkyl, is treated with an organometallic compound such as'R"MgBr to produce an addition compound of the type NMgBr v g .RI!

. Q-("J-(JH R0 0R R being-a lower alkyl radical. The latter is then reacted with an alkyl halide, e. g., RI, to form an alkanonitrile of the type I I GEN R' I Q (R0). it OR all symbols being of the definition as hereinabove.

. This nitrile is finally treated with an alkyl-metallo compound, e. g., alkylmagnesium bromide, to form the 2- alkanoneof the type (lower alkyl) 0:0 R" Q Q (R0 it OR The R groups are cleaved olf by hydrolysis. 7

Compounds of this invention are also useful in organic synthesis. Thus alkylation and acylation yield the ethers and the esters described in my copending application Serial No. 320,615, filed November 14, 1952.

The following examples illustrate in detail some of the construed as limited in spirit or in scope thereby. It will, be apparent to chemists skilled in the art that many modifications in materials and methods may be made without departing from the invention. In each of these examples, temperatures are given uncorrected in degrees centigrade and pressures during vacuum distillations in millimeters (mm.) of mercury.

The present application is a continuation-in-part of my copending'application, Serial No. 191,493, filed, October 2-1, 1950, now abandoned.

EXAMPLE 1 3,4-bis(p-meth0xyphenyl)-2-hexan0he A solution of parts of a,,B-bis-(p-methoxyphenyll v-aleronitrile in 700 parts of hot glacial acetic acid is treated with 570 parts of 48% hydrobromic acid and heated at refluxing temperature for 3 hours. Almost immediately after starting the reflux period, the solution becomes deeppurple-blue. The color changes to reddish-purple after 10 minutes and finally light Walnut-brown. The solution is then poured into 6000 parts of ice cold water. The fine, almost gelatinous, white precipitate is filtered and washed with water. After two recrystallizations from ethyl acetate, the a,fl-bis(p-hydroxyphenyl) -valeramide melts at about 274 to 275 C.

A copper vessel is charged with parts of a,/8-bis(phydroxyphenyDvaleramide, 850 parts of ethylene glycol and 96 parts of 33% aqueous sodium hydroxide. After refluxing for 24 hours the homogeneous reaction mixture relative amounts of materials in parts by weight is diluted with 3000 parts of water, filtered, acidified and allowed to stand overnight in the refrigerator. There is obtained by filtration crude cud-bis(p-hydroxyphenyl)- valeric acid, melting at 237240 C. Recrystallization from 90% acetic acid gives an analytically pure sample of the higher melting racemic isomer of d, 8-bis(p-hydroxyphenyl)valeric acid, which melts at about 244-246 C.

The aqueous filtrate from which the higher melting racemate has been obtained is evaporated in vacuo and extracted with ether to recover the low-melting racemic isomer of a,fi-bis(p-hydroxyphenyl) valeric acid. A sample of this isomer, recrystallized from water, melts at about 189 -190 C.

A solution of 29 parts of u,}9-bis(p-hydroxypheny1)- valeric acid, M. P. 244246 C., in 60 parts of methanol is mixed with 27 parts of dimethyl sulfate. After cooling to 5 C., a solution of 15 parts of potassium hydroxide in 35 parts of water is added all at once. After methylation ceases, the resultant mixture is diluted with water, acidified and extracted with ether. The ethereal layer is extracted with 5% aqueous sodium hydroxide to obtain the a,B-bis(p-methoxyphenyl)valeric acid free of a. small quantity of by-product methyl ester of the desired acid. The alkaline extract is acidified and again extracted with ether. The ether extract is dr ed over anhydrous potassium carbonate and evaporated to give a racemic 11,5- bis(p-m thoxyphenyl)valeric acid which melts at about 183-184" C. after recrystallization from ethanol.

To a suspension of 15.5 parts of a.B-bis(p-methoxyphenvllv leric acid in 300 parts of abs lute ether, 16.5 parts of thi nvl chl ride and 0.1 part of pyridine are added. After reflux ng for 90 minutes the solution is filtered a d evap rated to drvness at reduced pressure. The mR-hidn-m thnxvohenvl\valervl chloride. melting at 137-138 C.. diss lved in 45 parts f warm benzene. is added as ran rilv as oss ble to a boilinrz soluti n of 28 p rts f freshlv nrep red dime hvlc dmium in 2 0 p rts of ben ene. When the m ld v ex thermic rea tion subsides. extern he ting s utilized to mai tain the reacti n mixt e at T fiuxin tem erature for 75 minutes. The mi t re is then h l ed in an ice b h and carefn1lv dec p ed i h lfifiparts of 10% h drochloric acid. The ammm raver is se r ted and extracted with benzene. Th b nzene, s l tions are ombined, dried and evaporat d to drvness in vacuo. The 3.4-h s(n-methoxvnhenvU-Z- hQYgnflfl is recrystallized from ethanol and melts at about 141142 C.

EXAMPLE 2 3 .4-bi. v-acetoxvvhenyl) -2-h exanone A mix ure f 10 parts of afi-hi fn-hvdr xvnhenvllvol rir firit'l. 6? parts of nvridine. and 38 parts of acetic a hvd ide is he t d r 2% hours on a steam bath. The excess acetic anhvdride s dec mp sed with water and the mi t re diluted with 5 0 p rts of water to precipitate the afi-bis (o-acetoxyphenyDvaleric acid melting at about To a suspension f 14 parts of efi-bistp-acetoxvphenvl\va e c acid in 2 3 parts of bsol te ether. 11 parts of thi nvl chloride and 0.1 part of ovridine are added. After reflu ing for 5 h urs the solution is filtered and evaporated to drvness at reduced pressure. The a.B-bis(p-acetoxy.- phenyl)valeryl chloride, dissolved in 120 parts of warm benzene, is added as rapidly as possible to a solution of 28 parts of freshly prepared dimethyl-cadmium in 260 parts of benzene. When the mildly exothermic reaction subsides, external heating is used to maintain the reaction temperature at refluxing ran e for 3 hours. The mixture is then ch lled in an ice bath and carefully decomposed with 100 parts of hydrochloric acid. The aqueous layer is separated and extracted with benzene. The benzene solutions are combined. dried, and evaporated to dryness in vacuo. The 3,4-bis(p-acetoxvphenyl)-2-hexanone is recrystallized from ethanol and melts at about 143-144" C.

4 EXAMPLE 3 3,4-bis(p-hydroxyphenyl) -2-hexan0ne To one part of 3,4-bis(p-acetoxyphenyl)-2-hexanone dissolved in 40 parts of methanol are added two parts of potassium bicarbonate in 13 parts of water. The mixture is refluxed for 2% hours on the steam bath, diluted with 140 parts of water, filtered, and acidified. The white, powdery precipitate is filtered off and washed with water. It consists of 3,4-bis(p-hydroxyphenyl)-2-hexanone melting at about 22022l.5 C. The compound has the structural formula HOO( JH(JHOOH EXAMPLE 4 3,4- bis(p-methoxyphenyl) -3-methyl-2-hexanone' To a solution of 133 parts of ethyl magnesium bromide in 640 parts of absolute ether are added portionwise in 6 hour 76 parts of a,/3-bis(p-methoxyphenyl)acrylonitrile. After refluxing for 4 hours there are added dropwise in 5 minutes 80 parts of methyl iodide. The mixture is refluxed for one hour and then decomposed with ice and hydrochloric acid. The ethereal layer is separated, dried over anhydrous potassium carbonate and distilled to yield the mixture of two racemic isomers of a,fi-bis(p-methoxyphenyl)-a-methylvaleronitrile. This is a viscous white oil boiling at about 162-165 C. at 0.003 mm. pressure.

A solution of 40 parts of methyl magnesium bromide in 78 parts of ether is added to 46 parts of the afi-blS- (p-methoxyphenyl)-a-methylvaler0nitrile in 216 parts of dry xylene. The mixture is stirred and heated to remove 36 parts of ether by distillation. It is then refluxed for 24 hours, the internal temperature being about 126 C. The Grignard complex of the product is decomposed with ice and hydrochloric acid. This acidic mixture is refluxed for 1 hour to hydrolyze any remaining imino compound. The organic layer is then separated, dried, and distilled to give the product, a mixture of the two racemic isomers of 3,4-bis(p-methoxyphenyl)- 3-methyl-2-hexanone, boiling at about 166l67 C. at 0.003 mm. pressure.

EXAMPLE 5 3,4-bis(p-hydroxyphenyl)-3-methyl-2-hexanone A solution of 93 parts of 3,4-bis(p-methoxyphenyl)-3- methyl-Z-hexanone and 550 parts of freshly distilled pyridine hydrochloride is heated at reflux temperature for 30 minutes, cooled, diluted with 4000 parts of water, chilled and extracted with ether. The ether extract is dried over anhydrous calcium sulfate, filtered and evaporated to leave an oily residue. The latter is taken up in 2200 parts of 2% aqueous sodium hydroxide solution at a temperature of 10-18" C., washed with ether, acidified with dilute hydrochloric acid and extracted with ether. The ether extract is washed with saturated aqueous sodium bicarbonate solution, dried over anhydrous calcium sulfate, stirred with charcoal, filtered and evaporated. The 3,4bis(p-hydroxyphenyl)-3-methyl-2-hexanone is then obtained by vacuum distillation at about 180-185" C. and 0.2 mm. pressure as a viscous yellow oil. It has the structural formula C H; (ll 0 C2H5 H0O HOo H EXAMPLE 6 3,4-bis(p-methox vph enyl -3-ethyl-2-h eptanone A solution of 87 parts of methyl magnesium bromide in. 170 parts of ether is added to parts of afi-bw- (p-methoxyphenyl)-a-ethylhexanonitrile (cf. method of E. Kohler, Am. Chem. Journal, 35, 403, 1906) in 470 parts of dry xylene, with stirring. 80 parts of the ether are distilled off. The mixture is heated at reflux temperature for 24 hours. The resulting Grignard complex is decomposed with ice and hydrochloric acid and then heated at refluxing temperature for one hour. The organic layer is separated, dried and submitted to high vacuum distillation at about 175-185 C. and 0.2 mm. pressure. The resulting oil consists of a mixture of the two racemic isomers of 3,4-bis(p-methoxyphenyl)-3- ethyI-Z-heptanone, which has an infrared maximum at about 5.9 microns.

EXAMPLE 7 3,4-bis(p-hydrxyphenyl) -3-ethyl-2-heptanone A mixture of 100 parts of 3,4-bis(p-methoxyphenyl)- 3-ethyl-2-heptanone and 590 parts of freshly distilled pyridine hydrochloride is refluxed for a half hour, cooled, diluted with 5000 parts of water and extracted with ether. The ether extract is dried over anhydrous calcium sulfate, filtered and solvent stripped in vacuo. The residue is taken up in 2500 parts of a 2% aqueous sodium hydroxide solution at C., washed with ether, acidified with dilute hydrochloric acid and extracted with ether. This ether extract is washed with saturated sodium bicarbonate solution and with water, dried over anhydrous calcium sulfate, stirred with charcoal, filtered and evaporated. The residue, containing the 3,4-bis(p-hydroxyphenyl)-3- ethyl-Z-heptanone, is distilled at about 0.15 mm. pressure. At about 185*195 C. the ketone of the following structural formula is obtained 1 a nogtH-ficngon EXAMPLE 8 4,5-bis(p-methoxyphenyl) -3-heptanone The ethyl ester of a,fi-bis(p-methoxyphenyl)acrylic acid melting at 73-74 C. is prepared by Fischer esterification of the u, 8-bis(p-methoxyphenyl) acrylic acid. A solution of ethyl magnesium bromide is prepared from 54 parts of magnesium and 270 parts of bromoethane in 2800 parts of absolute ether, is treated with 330 parts of the ethyl ester of u,/8-bis(p-methoxyphenyl)acrylate in 2100 parts of ether and heated at reflux temperature for 30 hours. The mixture is then decomposed with dilute aqueous hydrochloric acid and the organic layer is separated, dried over anhydrous calcium sulfate and solvent stripped in vacuo. The residual oil is distilled at about 177179 C. and 0.7 mm. pressure.

EXAMPLE 9 4,5 -bis( p-hydraxyphenyl) -3-heptanone A mixture of parts of 4,5-bis(p-methoxyphenyl)-3- heptanone and 120 parts of pyridine hydrochloride is boiled under reflux for 30 minutes, treated with a large volume of ice water and extracted with ether. The extract is dried over anhydrous calcium sulfate, filtered and evaporated. The oily residue is taken up in 2% aqueous sodium hydroxide solution, washed with ether, acidified with dilute hydrochloric acid and extracted with ether. This extract is washed with a saturated aqueous solution of potassium bicarbonate, dried over anhydrous calcium sulfate, stirred with charcoal, filtered and evaporated. The residue is distilled at about 0.25 mm. pressure. The 4,5-bis(p-hydroxyphenyl)-3-heptanone is obtained as a viscous, light golden oil at about 182-190 C. It has the structural formula O C H 6 EXAMPLE 10 3 (m,p a dimethoxyphenyl) 4 (p methoxyphenyD- 3 methyl 2 hexanone 295 parts of a-(m,p-dimethoxyphenyl)-,8-(p-methoxyphenyl)acrylonitrile are dissolved in 2000 parts of henzene at 65 C. and treated in the course of 15 minutes with 570 parts of a 1.4 normal ethereal ethyl magnesium bromide solution and then heated at reflux temperature for 30 minutes. In the course of 15 minutes, 2400 parts of methyl iodide are added and refluxing is continued for 6 hours. The reaction mixture is decomposed with dilute hydrochloric acid and filtered to remove the small amount of 1-(p-methoxyphenyl)-2-(m,p dimethoxyphenyl) 1- penten-B-one. The filtrate is evaporated and the residue crystallized from ethanol. Crystals are obtained melting at about -97 C. The 'ethanolic mother liquor is evaporated and distilled at about 0.5 mm. pressure and 192- 197 C. to yield the lower melting racemic isomer of 2 methyl 2 (m,p dimethoxyphenyl) 3 (p-methoxyphenyl) valeronitrile.

Under a nitrogen atmosphere a solution of 340 parts of the higher melting racemic isomer in 3900 parts of xylene is stirred and treated in the course of 5 minutes with 1300 parts of a 2.25 normal ethereal methyl magnesium bromide solution at reflux temperature. An immediate yellow flocculent precipitate is formed, which later turns greenish and crystalline. Stirring and heating at reflux temperature is continued for 4 hours and the resulting grayish white pasty mixture is decomposed with a large excess of aqueous ammonium chloride solution. The organic layer is separated and the aqueous phase is extracted several times with ether. The combined organic layers are dried over sodium sulfate, filtered and solvent stripped in vacuo to yield the. 3-methyl-3-(m,p-dimethoxyphenyl)-4-(p-methoxyphenyl)-2-hexanone as a viscous golden oil which does not readily crystallize. It is distilled at about -183" C. and 0.2 mm. pressure, and shows a strong infrared absorption at 5.89 microns.

EXAMPLE ll 3 (m,p dihydroxyphenyl) 4 (p hydr0xyphenyl)- 3 methyl 2 hexanone A mixture of 70 parts of 3-(m,p-dimethoxyphenyl)-4- (p-methoxyphenyl)-3-methyl-2-hexanone and 60 parts of freshly distilled pyridine hydrochloride is heated at reflux temperature for 55 minutes, poured onto 2500 parts of ice and made acid to a pH of 1 by addition of hydrochloric acid. The resulting oily precipitate is separated and the aqueous layer extracted with ether. The oil is likewise taken-up in ether and the combined ether solutions are dried over calcium sulfate, stirred with charcoal and activated alumina and filtered. Evaporation of the ether yields an oil which darkens on exposure to air. The resulting 3- (m,p-dihydroxyphenyl) -4- (p-hydroxyphenyl) 3-methyl-2-hexanone shows characteristic infrared absorption maxima at 2.8 microns and 5.88 microns. It has the structural formula wherein R is a member of the class consisting of hydrogen and lower alkyl radicals and n is a positive integer smaller than 3.

7 "8 A compound of the structural formula 8. A'comp'ound ofthe structural formula 1 1 l I 1 met 8 W v filower alky lower lky I (lower alkyl) ('30 (HO); (lower alkyl) OH 9. A compound of the structural formula 3 ('90 c H O 6 H0 CH- H -OH l 1 H (ower a ky 02H: 10 O C1115 I 0 02B! A compound of the structural formula HO (IIJAEHC OH 1 ogvera kyl) (llower lky H OH: H0C o -0H References Cited in the file of this patent loweralkyl) UNITED STATES PATENTS A compound of the structural formula 3 6 531261 May 1942 CH 2,455,535 Tallrnan Dec. 7, 1948 02115 OTHER REFERENCES OJ g 30 5501115; Am. Chem. Journal, vol. 35 (1906), pp. 386- Mills et a1.: J. Chem. Soc., vol. 27 1925 pp. 2475- Levy et a1.: Bull. Soc. Chim., Series and vol. f (1929), pp. 941-950. 00 CIHS 35 Baker: I. Am. Chem. Soc., vol. (1943), pp. 1572- 0 C Q Satriand et al.: Jour. Am. Chem. Soc., vol. 73 (1951), 

1. A COMPOUND OF THE STRUCTURAL FORMULA 